Temperature-regulating apparatus



May 27, 1930. J; H. PAYNE 1,760,520

TEMPERATURE REGULATING APPARATUS F1193 May 22, 1928 Inventcr: JohnHPayna. y

His Attorney Patented May .27, 1930 UNITED STATES,

PATENT OFFICE JOHN H. PAYNE, OF BALLSTON SPA, NEW YORK, ASSIGNOB 'I'OGENEBAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK Application filedMay 22,

- sparking at the contacts of a heat responsive element utilized toregulate the heating current of a body which is required to bemaintained at a substantially constant temperature. Thus in themanufacture of pie zo electric crystals from a chemical solution, forexample,-injurious sparking between the contacts of the heat responsiveelement is likely to prevent the fine degree of temperature regulationwhich is required for the proper growth of the crystal. In accordancewith my invention, this difliculty is avoided by the provision of animproved temperature regulating apparatus including a space dischargedevice which has its grid potential controlled in accordance with thetemperature of the body to be heated.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing and itsscope will be pointed out in;

the appended claims.

The drawing diagrammaticallyillustrates a temperature regulatingapparatus wherein my invention has been embodied.

This apparatus comprises a heating element 1 located within a vessel 2and arranged to be connected to a suitable source of heating currentthrough switches 3 and 4 and supplyterminals 5.. The switch 3 is biasedto its open position by a spring 6 and is provided with a closing coil 7which is arranged to be connected to the supply leads 5 through theswitch 4, a space discharge device 8 and a pair of resistors 9 and 10.The space dischargedevice 8 includes an anode 11, a cathode 12, and agrid 13 which is connected to the cathode 12 through impedance devicesshown as a resistor 14 and resistor 10. The grid potential of the device8 is controlled 1928. Serial 1T0. 279,812.

by a heat responsive element 15 mounted in the vessel 2 and providedwith a solid contact 16 and a liquid contact 17 which assumes a positiondependent on the temperature within the vessel 2. 4

Assuming the current supply terminals 5 to have the polarities indicatedin the drawing, sufficient current is-transmitted through the device 8to close the switch 3 only when the contacts 16 and 17 of the heatresponsive element 15 are disengaged from one another.

Thus'when the contacts 16 and 17 are disengaged from one another thegrid 13 is connected to the positive terminal through the resistor 14and tends to assume a positive potential with respect to the cathode.When the contacts 16 and 17 are in engagement with one another, however,the resistor 14 is connected between the supply terminals 5 with thegrid at the negative terminal and insufficient current to operate theswitch 3 is transmitted through the device.

When the grid 13 is connected to the positive supply, terminal throughthe resistor 14, it is subjected to'a positive bias potential of amagnitude dependent on the potential drop produced in the resistorlO bythe cathode heating currents of the device 8. When the grid 13 isconnected to the negative supply terminal through the device 15, it issubjected to a negative bias potential dependent on the potential dropproduced in the resistor. 9 by the cathode heating current. These biaspotentials are of advantage in that they tend to maintain the current ofthe device 8 at a value which is either slightly above or'below thatrequired to operate the switch 3 so that the switch 3 is very sensitiveto change in the relation between the contacts of the heat responsiveelement 15.

It has been found that the resistance of resistor 14 should be madefairly high in order to prevent sparking at the contactsvof the device15. The particular value of resistance to be used in each case will of.course depend on the electrical constants of the other-parts of theapparatus. In the practical operation of the apparatus, a resistance ofone to ten thousand ohms has been found. satisfactory.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. The combination of a heat producing element, a switch provided withan operating coil and arranged to transmit heating current to saidelement, a space discharge device provided with a cathode and an anodefor transmitting operating current to said cOil and with a grid forcontrolling said operating current, means in circuit with said cathodeproviding a positive and a negative biasing potential with respect tosaid cathode, means including a resistor for applying one of saidbiasing potentials to said grid, and means including a contact andclosure means therefor operable in response to the heat produced by saidheating element for applying the other of said biasing potentials tosaid grid.

2. The combination of a heat producing clement, electrical currentsupply terminals, a switch provided with an operating coil and arrangedto interconnect said element with said terminals, a space dischargedevice provided with a cathode and anode connected between saidterminals through said operating coil and with a grid, an impedancedevice connected between said grid and one of said terminals, and acircuit control device operated in accordance with the heat of saidelement and connected between said grid and the other of said terminals.

'3. The combination of a heat producing clement, means for controllingthe supply of heating current to said element, a space discharge devicearranged to control the energizationof said control means and providedwith a grid for controlling the current transmitted between its cathodeand anode, terminals for supplying heating current to said cathode, animpedance device connected between said grid and one of said terminals,and a circuit control device arranged to operate in accordance with theheat of said element and connected between said grid and the other ofsaid terminals.

4. The combination of a space discharge device provided with a cathodeand an anode and with a grid for controlling the current transmittedbetween said cathode and anode, a pair of terminals for supplyingheating current to said cathode, an impedance device connected betweensaid grid and one or said terminals, and a circuit control deviceconnected between said grid and the other of said terminals.

5. The combination of a space discharge device provided with a cathodeand an anode and with a rid for controlling the current transmittedetween said cathode and anode, a pair of terminals for supplying heatingcurrent to said cathode, impedance devices each connected between-saidcathode and a different one of said terminals, an impedance deviceconnected between said grid and one of said terminals, and meansarranged to connect said grid to the other of said terminals. In witnesswhereof, I have hereunto set my hand this 21st day of May, 1928.

JOHN H. PAYNE.

